The borders agency fails immigrants in ways that defy understanding.

The unknown whereabouts of 150,000 people refused residency in Britain made headlines this week. The UK Border Agency took the usual flack for failing to exercise a "clear strategy" to deal with these cases. A Labour MP playing two populist cards with one hand – immigration and bonuses – demanded the removal of bonuses from senior UKBA officials. The pattern is a familiar one.

Yet there are far worse practices for which the border agency ought to be held to account. It is troubling barometer of public opinion that this is the issue that we choose to get up in arms about when far greater injustices occur within the immigration system on a daily basis.

Gladys, a young dental nurse from Zimbabwe, is just one typical victim out of thousands, whose liberty depends on the caprice of border agency decision making. She spent six months imprisoned at Yarl's Wood immigration removal centre. Not because she posed a security threat or was a danger to the British public, but because of a series of arbitrary decisions. I interviewed Gladys last December while she was still detained at Yarl's Wood.

Before being detained, Gladys reported to the border agency’s Solihull centre every three months while her asylum application was being processed. As an asylum seeker Gladys was ineligible for benefits and, like all asylum seekers with cases pending, was barred from working, making the £7 train fare from Wolverhampton to Solihull an impossible expense.

She explained the difficulty of her situation to the border agency. They reacted, perversely, by making her appointments fortnightly. Of course, Gladys could no better cough up £7 every two weeks, than every three months, and once again she appealed to their common sense. The response was an unannounced visit from the six immigration officers, who searched her, and carried her off to Yarl’s Wood. "Strangely I was just at peace. I didn’t think I would be detained for this long," she told me.

Inside Yarl’s Wood, things quickly got worse. When Gladys made an application for bail from Yarl’s Wood, the agency claimed to have no record of her initial asylum claim. This meant she had start her entire asylum application from scratch; further prolonging the already slow and cumbersome process. The cloud of uncertainty which Gladys hoped might end with a decision on her future looked set to continue. Why?

It turned out the agency had misspelt her name on the first application, and so when she made a bail application with her name spelt correctly, they failed to match up the two files. This revelation did not nudge the conscience or common sense of any official; the process had to begin again. "The whole system can be so frustrating," Gladys said. "It’s like they play mind games with you."

Gladys’ punishment continued when she refused to board a flight to Zimbabwe while her asylum claim was still in progress. Yarl’s Wood staff, (the centre is run by Serco, who took over from G4S in 2007) suddenly stopped her working the weekly nine-hour shifts available to all the women detained. The pay is one pound an hour and helps pay for toiletries and phone credit.

Gladys spent much of her time at Yarl’s Wood in fear; fear that she would get ill and the staff would not believe her; fear of what would happen if she was deported and left at Harare Airport; fear of being forgotten. "I am just a number. CID number 404. You go crazy. A lot of people are suicidal. If you don’t believe in something you will lose your mind."

The psychological effects of indefinite detention for immigration purposes have been well documented in Lancet and the Medical Journal of Australia (MJA). The MJA has reported of detainees "dominated by hopelessness" engaging in "repeated acts of self-harm or self-mutilation leading to acute hospital admissions."

It is not difficult to see how this might come about; the centres are effectively prisons. I remember my initial shock at the level of security on my first visit to a removal centre. I signed a form agreeing to be searched, provided two forms of identification, and had my fingerprints taken. I was not allowed to take anything up to the visitors’ room and had to leave all my belongings in a locker. I asked the guard if I could take my dictaphone or notebook; no. I was escorted to a small room and searched; I took off my shoes and emptied my pockets. A tiny hair pin fell from a pocket and was confiscated. Each visit I scan my now officially-remembered fingerprint three times before I am can enter the visitors’ room.

Sarah (not her real name), a sensitive and reserved 24-year-old detained at Yarl’s Wood is feeling the impact of being detained eight months in these conditions, while she appeals against the refusal of her asylum claim. She hates to complain, but yearns for a little kindness. "I don’t want to go mad," she says. "I try not to hold it in my heart...it’s not easy." She cannot sleep, suffers constant headaches, but refuses to visit the centre’s nurse because for fear of being called a liar.

Sarah and Gladys contrast starkly. Gladys was happy to be interviewed, to be asked questions, and to challenge her treatment. Since being released, she has continued to campaign vocally against immigration detention. But Gladys is the exception among the 3,000 odd detention estate (the highest since 2001). Sarah is more typical; languishing alone, voiceless and forgotten. She will never make the headlines.

Rebecca Omonira-Oyekanmi reports and writes on immigration, women and economics, housing, legal aid, and mental health. Read her latest work here. Her blog rebeccaomonira.com was shortlisted for the 2012 Orwell Prize. She tweets @Rebecca_Omonira.